C16 Peptide Promotes Vascular Growth and Reduces Inflammation in a Neuromyelitis Optica Model

Effects of intravenous pulse methylprednisolone in neuromyelitis optica during the acute phase

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) is an anti-aquaporin 4 (anti-AQP4) autoantibodies-mediated idiopathic inflammatory demyelinating disease of the central nervous system. While intravenous pulse methylprednisolone (IVMP) is the recommended initial treatment option for acute onset NMOSD, its therapeutic mechanism remains unclear. We hypothesized that IVMP would reduce the expression of pro-inflammatory factors and increase the resolution of inflammation in patients with NMOSD.

METHODS

Mendelian randomization (MR) analysis was used to screen meaningful inflammatory and resolution factors for inclusion. Three MR methods with inverse variance weighting (IVW) were primarily used to identify positive results. Interleukin (IL)-10, IL-1β, IL-6, C-X-C motif chemokine ligand 12 (CXCL12), and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) were screened from 41 inflammatory factors, and resolvin D1 (RvD1), maresin 1 (MaR1), and lipoxin A4 (LXA4) were screened from 6 resolution markers for inclusion. Subsequently, 12 patients with NMOSD were enrolled and treated with IVMP. Serum levels of the aforementioned inflammatory and resolution markers were measured by enzyme-linked immunosorbent assay before and after IVMP treatment.

RESULTS

High levels of TRAIL, CXCL12, and IL-1β were associated with an increased risk of NMOSD (TRAIL: odds ratio [OR], 1.582; 95% confidence interval [CI], 1.003-2.495; CXCL12: OR, 3.610; 95% CI, 1.011-12.889; IL-1β: OR, 4.500; 95% CI, 1.129-17.927). High levels of RvD1, MaR1, and LXA4 were associated with a reduced risk of NMOSD (RvD1: OR, 0.725; 95% CI, 0.538-0.976; MaR1: OR, 0.985; 95% CI, 0.970-0.999; LXA4: OR, 0.849; 95% CI, 0.727-0.993). Among patients with NMOSD, serum levels of IL-6, CXCL12, and TRAIL significantly decreased following IVMP treatment, compared with pretreatment levels, while levels of IL-1β, LXA4, and MaR1 significantly increased after IVMP treatment (p < 0.05). A significant positive correlation was observed between CXCL12 levels and Expanded Disability Status Scale (EDSS) scores (r = 0.451, p < 0.05).

CONCLUSION

Several systemic inflammatory regulators associated with the pathogenesis of NMOSD were identified. The protective roles of LXA4 and MaR1 may be indispensable components of glucocorticoid treatment. Therefore, the use of resolution markers may be a potential strategy for improving central nervous system injury in individuals with NMOSD.

Neuroprotective effects of a novel peptide through the Rho-integrin-Tie2 and PI3K/Akt pathways in experimental autoimmune encephalomyelitis model

Purpose: The interaction between inflammatory cells and integrin in the endothelium plays a key role during infiltration. Previous evidence has shown that synthetic C16 peptide selectively binds to integrins αvβ3 and α5β1 and exhibits a neuroprotective effect. It has also been reported to inhibit the differentiation of microglia into the M1 (pro-inflammatory) phenotype while promoting its differentiation to the M2 (anti-inflammatory) phenotype. This study aimed to investigate the mechanisms of action of the C16 peptide in multiple sclerosis using a rodent model. Methods: Molecular, morphological, and neurophysiological assays were used to investigate the neuroprotective effects of C16 peptide and related signaling pathways in a model of EAE. Results: The results showed that C16 significantly improved the clinical score and cortical somatosensory/motor evoked potential. It also alleviated inflammatory responses, including microglial activation and leukocyte infiltration, relieved the impairment of the brain blood barrier and edema, and reduced neuronal apoptosis, axonal loss, and demyelination induced by EAE. The C16 peptide increased the expressions of pTie-2 and Tie-2, integrin αvβ3, and α5β1 and activated the PI3K/Akt signal pathway but decreased the expression of Rho. Co-treatment of C16 with Tie-2 inhibitor and PI3K inhibitor LY294002 attenuated these effects of C16. Conclusion: The C16 peptide demonstrated neuroprotection in the EAE model through the integrin, Tie-2, and PI3K/Akt signaling pathways, and it could be a potential strategy for treating inflammation-related diseases in the central nervous system.

Novel nano-carriers with N-formylmethionyl-leucyl-phenylalanine-modified liposomes improve effects of C16-angiopoietin 1 in acute animal model of multiple sclerosis

Gradual loss of neuronal structure and function due to impaired blood-brain barrier (BBB) and neuroinflammation are important factors in multiple sclerosis (MS) progression. Our previous studies demonstrated that the C16 peptide and angiopoietin 1 (Ang-1) compound (C + A) could modulate inflammation and vascular protection in many models of MS. In this study, nanotechnology and a novel nanovector of the leukocyte chemotactic peptide N-formyl-methionyl-leucyl-phenylalanine (fMLP) were used to examine the effects of C + A on MS. The acute experimental autoimmune encephalomyelitis (EAE) model of MS was established in Lewis rats. The C + A compounds were conjugated to control nano-carriers and fMLP-nano-carriers and administered to animals by intravenous injection. The neuropathological changes in the brain cortex and spinal cord were examined using multiple approaches. The stimulation of vascular injection sites was examined using rabbits. The results showed that all C + A compounds (C + A alone, nano-carrier C + A, and fMLP-nano-carrier C + A) reduced neuronal inflammation, axonal demyelination, gliosis, neuronal apoptosis, vascular leakage, and BBB impairment induced by EAE. In addition, the C + A compounds had minimal side effects on liver and kidney functions. Furthermore, the fMLP-nano-carrier C + A compound had better effects compared to C + A alone and the nano-carrier C + A. This study indicated that the fMLP-nano-carrier C + A could attenuate inflammation-related pathological changes in EAE and may be a potential therapeutic strategy for the treatment of MS and EAE.

Ultrashort lipo-tetrapeptide with potent antibacterial activity and local therapeutic effect against Staphylococcus aureus

OBJECTIVES

Mastitis in dairy cows is a common infectious disease on dairy farms and a major danger to the dairy industry. The harmful bacteria with the greatest clinical isolation rate are Staphylococcus aureus. As a result, bacterial mastitis in dairy cows can lead to decreased milk output, quality, and costs. Traditional antibiotics are currently used to treat mastitis in dairy cows. Nonetheless, long-term usage of high doses of antibiotics increases the risk of the establishment of drug-resistant strains, and the problem of drug residues is becoming more prevalent. We investigated the antibacterial effects of varying molecular side chain length lipopeptides on Staphylococcus aureus ATCC25923 and GS1311 using five tetrapeptide ultrashort lipopeptides developed and synthesised in this study.

METHODS

To evaluate the application value of the synthesized lipopeptides in the prevention and treatment of mastitis, the lipopeptides with the best antibacterial action were chosen for safety testing and a mouse mastitis model treatment test.

RESULTS

Three of the lipopeptides produced have strong antibacterial properties. Within the drug's safe concentration range, C16KGGK has an excellent antibacterial action and can have a therapeutic influence on mastitis induced by Staphylococcus aureus infection in mice.

CONCLUSION

The findings of this study can be used to develop new antibacterial medications and their therapeutic application in the treatment of mastitis in dairy cows.

Synthetic Cationic Lipopeptide Can Effectively Treat Mouse Mastitis Caused by Staphylococcus aureus

Mastitis caused by Staphylococcus aureus (S. aureus) in dairy cows is one of the most common clinical diseases in dairy cattle. Unfortunately, traditional antibiotic treatment has resulted in the emergence of drug-resistant strains of bacteria, making this disease more difficult to treat. Therefore, novel lipopeptide antibiotics are becoming increasingly important in treating bacterial diseases, and developing novel antibiotics is critical in controlling mastitis in dairy cows. We designed and synthesized three cationic lipopeptides with palmitic acid, all with two positive charges and dextral amino acids. The lipopeptides' antibacterial activity against S. aureus was determined using MIC and scanning electron microscopy. The safety concentration range of lipopeptides for clinical usage was then estimated using the mouse erythrocyte hemolysis assay and CCK8 cytotoxicity. Finally, lipopeptides with high antibacterial activity and minimal cytotoxicity were selected for the treatment experiments regarding mastitis in mice. The observation of histopathological changes, bacterial tissue load and expression of inflammatory factors determined the therapeutic effects of lipopeptides on mastitis in mice. The results showed that all three lipopeptides displayed some antibacterial activity against S. aureus, with C16dKdK having a strong antibacterial impact and being able to treat the mastitis induced by S. aureus infection in mice within a safe concentration range. The findings of this study can be used as a starting point for the development of new medications for the treatment of mastitis in dairy cows.

Not All Lectins Are Equally Suitable for Labeling Rodent Vasculature

The vascular system is vital for all tissues and the interest in its visualization spans many fields. A number of different plant-derived lectins are used for detection of vasculature; however, studies performing direct comparison of the labeling efficacy of different lectins and techniques are lacking. In this study, we compared the labeling efficacy of three lectins: Griffonia simplicifolia isolectin B4 (IB4); wheat germ agglutinin (WGA), and Lycopersicon esculentum agglutinin (LEA). The LEA lectin was identified as being far superior to the IB4 and WGA lectins in histological labeling of blood vessels in brain sections. A similar signal-to-noise ratio was achieved with high concentrations of the WGA lectin injected during intracardial perfusion. Lectins were also suitable for labeling vasculature in other tissues, including spinal cord, dura mater, heart, skeletal muscle, kidney, and liver tissues. In uninjured tissues, the LEA lectin was as accurate as the Tie2–eGFP reporter mice and GLUT-1 immunohistochemistry for labeling the cerebral vasculature, validating its specificity and sensitivity. However, in pathological situations, e.g., in stroke, the sensitivity of the LEA lectin decreases dramatically, limiting its applicability in such studies. This work can be used for selecting the type of lectin and labeling method for various tissues.

Combined treatment with C16 peptide and angiopoietin-1 confers neuroprotection and reduces inflammation in 3-nitropropionic acid-induced dystonia mice

Dystonia is a disorder associated with abnormalities in many brain regions including the basal ganglia and cerebellum. The toxin 3-Nitropropionic acid (3-NP) can induce neuropathologies in the mice striatum and nigra substance, including excitotoxicity, neuroinflammation, and extensive neuronal atrophy, characterized by progressive motor dysfunction, dystonia, and memory loss, mimicking those observed in humans. We established a mouse model of dystonia by administering 3-NP. Given the reported neuroprotective effects of the endothelial growth factor angiopoietin-1 (Ang-1) and the anti-inflammatory integrin αvβ3 binding peptide C16, we performed this study to evaluate their combined effects on 3-NP striatal toxicity and their therapeutic potential with multiple methods using an in vivo mouse model. Sixty mice were equally and randomly divided into three groups: control, 3-NP treatment, and 3-NP+C16+Ang-1 treatment. Behavioral and electrophysiological tests were conducted and the effect of the combined C16+Ang-1 treatment on neural function recovery was determined. We found that C16+Ang-1 treatment alleviated 3-NP-induced behavioral, biochemical, and cellular alterations in the central nervous system and promoted function recovery by restoring vascular permeability and reducing inflammation in the micro-environment. In conclusion, our results confirmed the neuroprotective effect of combined C16+Ang-1 treatment and suggest their potential as a complementary therapeutic against 3-NP-induced dystonia.